dbus:cli: implement io.netplan.Netplan.Generate() (#208)

Proxy the 'netplan generate' CLI via DBus, if called from within a snap,
to work around the strict AppArmor confinement.

see: snapcore/snapd#10212

COMMITS:
* dbus:cli: implement io.netplan.Netplan.Generate()
Proxy the 'netplan generate' CLI via DBus, if called from within a snap,
to work around the strict AppArmor confinement.
see: https://github.com/snapcore/snapd/pull/10212
* doc: mention Netplan.Generate() DBus method

1 files changed, 30 insertions, 0 deletions

diff --git a/src/dbus.c b/src/dbus.c
index d2eac4d..f0aa53a 100644
--- a/src/dbus.c
+++ b/src/dbus.c
@@ -239,6 +239,35 @@ method_apply(sd_bus_message *m, void *userdata, sd_bus_error *ret_error)
 }
 
 static int
+method_generate(sd_bus_message *m, void *userdata, sd_bus_error *ret_error)
+{
+    g_autoptr(GError) err = NULL;
+    g_autofree gchar *stdout = NULL;
+    g_autofree gchar *stderr = NULL;
+    gint exit_status = 0;
+
+    gchar *argv[] = {SBINDIR "/" "netplan", "generate", NULL};
+
+    // for tests only: allow changing what netplan to run
+    if (getenv("DBUS_TEST_NETPLAN_CMD") != 0)
+       argv[0] = getenv("DBUS_TEST_NETPLAN_CMD");
+
+    g_spawn_sync("/", argv, NULL, 0, NULL, NULL, &stdout, &stderr, &exit_status, &err);
+    // LCOV_EXCL_START
+    if (err != NULL)
+        return sd_bus_error_setf(ret_error, SD_BUS_ERROR_FAILED,
+                                 "cannot run netplan generate: %s", err->message);
+    g_spawn_check_exit_status(exit_status, &err);
+    if (err != NULL)
+       return sd_bus_error_setf(ret_error, SD_BUS_ERROR_FAILED,
+                                "netplan generate failed: %s\nstdout: '%s'\nstderr: '%s'",
+                                err->message, stdout, stderr);
+    // LCOV_EXCL_STOP
+
+    return sd_bus_reply_method_return(m, "b", true);
+}
+
+static int
 method_info(sd_bus_message *m, void *userdata, sd_bus_error *ret_error)
 {
     sd_bus_message *reply = NULL;
@@ -663,6 +692,7 @@ method_config(sd_bus_message *m, void *userdata, sd_bus_error *ret_error)
 static const sd_bus_vtable netplan_vtable[] = {
     SD_BUS_VTABLE_START(0),
     SD_BUS_METHOD("Apply", "", "b", method_apply, 0),
+    SD_BUS_METHOD("Generate", "", "b", method_generate, 0),
     SD_BUS_METHOD("Info", "", "a(sv)", method_info, 0),
     SD_BUS_METHOD("Config", "", "o", method_config, 0),
     SD_BUS_VTABLE_END